Wasim bought two cricket bats for Rs. 840 and Rs. 360 respevtively. He sells the first bat at a gain of 15% and the second one at a loss of 5%. Find his gain or loss per cent in the whole transaction.

Answer

To solve the problem step by step, we will calculate the selling prices of both bats, then determine the total cost price and total selling price, and finally calculate the overall gain or loss percentage.

### Step 1: Calculate the Selling Price of the First Bat
- **Cost Price (CP) of First Bat** = Rs. 840
- **Gain Percentage** = 15%

To find the Selling Price (SP) of the first bat, we use the formula:
\[ SP = CP + \left(\frac{Gain \%}{100} \times CP\right) \]
Substituting the values:
\[ SP_1 = 840 + \left(\frac{15}{100} \times 840\right) \]
\[ SP_1 = 840 + 126 = 966 \]

### Step 2: Calculate the Selling Price of the Second Bat
- **Cost Price (CP) of Second Bat** = Rs. 360
- **Loss Percentage** = 5%

To find the Selling Price (SP) of the second bat, we use the formula:
\[ SP = CP - \left(\frac{Loss \%}{100} \times CP\right) \]
Substituting the values:
\[ SP_2 = 360 - \left(\frac{5}{100} \times 360\right) \]
\[ SP_2 = 360 - 18 = 342 \]

### Step 3: Calculate the Total Cost Price and Total Selling Price
- **Total Cost Price (CP)** = CP of First Bat + CP of Second Bat
\[ Total \, CP = 840 + 360 = 1200 \]

- **Total Selling Price (SP)** = SP of First Bat + SP of Second Bat
\[ Total \, SP = 966 + 342 = 1308 \]

### Step 4: Calculate Overall Gain or Loss
- **Gain or Loss** = Total SP - Total CP
\[ Gain = 1308 - 1200 = 108 \]

### Step 5: Calculate Gain Percentage
To find the Gain Percentage, we use the formula:
\[ Gain \% = \left(\frac{Gain}{Total \, CP}\right) \times 100 \]
Substituting the values:
\[ Gain \% = \left(\frac{108}{1200}\right) \times 100 \]
\[ Gain \% = 9 \]

### Final Answer
Wasim's overall gain percentage in the whole transaction is **9%**.

---